1. Technical Field
The present disclosure relates to an auxiliary drive of a combustion machine, in particular of a combustion machine of a utility vehicle.
2. Description of Related Art
Combustion machines of utility vehicles often have a power take-off which serves for the drive of appliances or auxiliary assemblies. For this purpose, it is known for a shaft of the auxiliary drive to be driven by a crankshaft of the combustion machine via intermediate gears. For example, the laid-open specification EP 1 174 605 A2 has disclosed for example an auxiliary drive of a combustion machine comprising a shaft which is guided in a case by way of radial and axial bearings and which is connected rotationally conjointly to a gearwheel, wherein said gearwheel can be driven by a crankshaft of the combustion machine via intermediate gears, and the shaft, at its free end, has a drive-output flange, which is connected rotationally conjointly to the shaft, for the purposes of driving working machines. Here, the shaft is integrated with the radial and axial bearings and the gearwheel into the crankcase of the combustion machine, wherein the gearwheel is arranged so as to be situated directly between the radial bearings.
It is also known that modern combustion machines have numerous auxiliary assemblies. Aside from auxiliary assemblies which are directly required for the operation of the vehicle engine, such as for example alternator, water pump or compressor, increasing use is being made of auxiliary assemblies which are intended two improve the comfort of the vehicle, for example air-conditioning compressors, steering assistance pumps etc. Normally, said auxiliary assemblies are fastened to the vehicle engine and are driven by the latter via chain drives, belt drives, gearwheel drives or a combination of these. The greater the number of auxiliary assemblies provided in a vehicle, the more difficult it becomes in spatial terms for these to be fastened in a suitable manner to the vehicle engine, and the more cumbersome and complicated the required drives become. Such a multiplicity of auxiliary assemblies and belt drives or the like poses difficulties not only owing to the engine bay, which nowadays is generally of very tight dimensions.
FIG. 1 shows a perspective view of an arrangement 10, known from the prior art, of auxiliary assemblies of an internal combustion engine. This is an internal combustion engine 1, in the form of a diesel combustion machine, of a utility vehicle. The internal combustion engine 1 is closed off at the bottom by an oil sump 19. The top side of the internal combustion engine 1 is denoted by the reference designation 5. On the front face side 4 of the internal combustion engine 1 there is situated a belt mechanism 6, hereinafter referred to for short as belt drive, which is driven by the combustion machine. In the perspective view of FIG. 1, the reference designation 6b denotes the belt, and the reference designation 6a denotes a drive belt pulley. In a known manner, the belt drive drives a 24 V generator (alternator) 11, a water pump 12 and a refrigerant compressor 13 of the air-conditioning system. The water pump 12 and refrigerant compressor 13 are likewise arranged, behind the fan 7, on the front face side 4, but on the rear part (not shown in FIG. 1) of the front face side 4, and thus on that side of the front face side 4 which is situated opposite the generator 11.
Also situated on the front face side 4 is a front gear drive (gearwheel mechanism) which is driven by the combustion machine and the gearwheels of which are encased by the control case 51 and which are thus not visible in the illustration of FIG. 1. The front gear drive drives the fan 7 arranged on the front face side 4, a high-pressure fuel pump 15 arranged laterally on the crankcase 2, and an oil pump. Furthermore, a rear gear drive is provided, that is to say a gear drive which is arranged on the gearbox-side face side 3 of the internal combustion engine 1, which gear drive is driven by the internal combustion engine. The rear gear drive is encased by the control case 52, and is therefore not visible in the illustration of FIG. 1. The crankcase 2 is open to the face sides 3, 4, and is closed off at the face sides by the control cases 51, 52, in which the gear drives are accommodated.
The rear gear drive drives an air compressor 14, also referred to as air impeller, which is in the form of a piston-type compressor. The air compressor 14 supplies compressed air to a compressed-air system of the utility vehicle. The air compressor is fastened to a lower rear section of the lateral wall of the crankcase. At this location, an opening is provided in the crankcase 2, via which opening the power flow between compressed-air compressor 4 and the rear gear drive is realized.
The rear gear drive furthermore drives a steering assistance pump which is arranged on the air compressor 14. The rear gear drive output furthermore, in a known manner, drives the camshaft drive input, and has an auxiliary drive (power take-off) for the drive of, for example, a hydraulic pump for body systems of the utility vehicle (in each case not illustrated).
By way of such a design, the available free structural space is virtually fully utilized for the arrangement of auxiliary assemblies such as are required for conventionally equipped motor vehicles. Problems however arise in the case of equipment with further auxiliary assemblies, for example if the utility vehicle is to be equipped with a system for waste heat recovery (WHR), in the case of which, for example, it is sought to use an expansion machine.